Iowa Sen. Chuck Grassley said today he won’t endorse a presidential candidate before the Iowa caucuses.

“I made a decision that I’m not going to endorse anybody,” he said during a conference call with reporters. “We’ve got several good candidates and I think I’m wiling to let the system go and I also feel that at this point, my involvement would not make a significant difference because our Republicans are divided among so many different candidates,” he said.

He said he thinks the caucus winner would be doing well to get 25 percent of the vote on caucus night.

That Grassley is hanging back tends to reinforce the idea that the Republican nomination battle remains a wide-open race. Not to say Grassley would only back a sure thing, but he’s savvy enough to calculate the risk-reward ratio of wading into such a volatile situation. Don’t be surprised if Gov. Terry Branstad does the math and comes up with the same answer.